In recent years, there has been increasing concern over the availability of worldwide supplies of crude oil and other fluid hydrocarbon feedstocks and fuels. There have similarly been concerns about the emission of undesirable materials into the atmosphere upon combustion of fuels, such as gasoline, in internal combustion engines. These concerns have led to attempts to require the use of reformulated gasolines in areas of acute air pollution such as California. California has enacted requirements for a Phase 2 California reformulated gasoline for gasoline used in California. (Title 13 C.C.R, Sections 2250-2273 (including test method amendments effective Sep. 27, 2001)). These fuel specifications are referred to herein as “California formulated gasoline specifications.” The requirements of ASTM D4814-01a (Approved Nov. 10, 2001), hereby incorporated by reference, are widely applicable, to gasolines produced in the United States, but various countries, states and local governmental entities may apply other or additional requirements. This concern for cleaner burning gasolines has resulted in requirements for gasolines that require more refining to produce the desired properties in the gasoline. Typically, the gasolines produced today have an octane requirement of a minimum octane of 87 for regular gasoline or a 92 minimum octane for premium gasoline. The octane values referred to are a combination of the research motor octane number plus the motor octane number divided by two, i.e. (R+M)/2. These fuels typically require the production in a refining operation of high-octane blending components. Typically, such high-octane blending components are produced in alkylation and reforming units. In some instances addition of dimers of isobutene or isobutene with n-butene may be used to increase octane. The reformate is more highly aromatic than the fuels produced by alkylation or dimerization of butenes. These materials alone or in combination are typically used as octane enhancers in gasoline blends. Operation of octane enhancing units, such as alkylation units and reformers, is relatively energy intensive and requires substantial quantities of natural gas or other energy sources. As a result of the processing, some of the feedstocks are lost to unusable products. As a result of this requirement for higher octane blending components coupled with the requirement for specific compositional requirements in the reformulated gasoline, more crude oil or other gasoline component feedstocks are required to produce a given quantity of gasoline than was previously the case.
In the production of reformulated gasoline, added refining steps are necessary to produce the desired amount of high octane blending components while removing undesirable compounds and modifying the properties of other fuel blending streams (such as by isomerization of C5 range paraffins and the like) to meet the rather stringent distillation and other requirements of reformulated gasoline. The net result has been an increase in the refining expense and in the amount of crude oil required to produce the reformulated gasoline by comparison to gasoline meeting the requirements of ASTM D4814-01a. While the use of reformulated gasoline is considered to have been an improvement in reducing emissions from automotive engines fueled with reformulated gasoline, the emission of pollutants to the atmosphere from engines fueled with reformulated gasoline must be considered in combination with the increased emissions to the atmosphere from the refineries producing such fuels, especially carbon dioxide, which has been the subject of attention recently with respect to possible greenhouse effects.